Update dexie.d.ts to version 1.2
Update dexie.d.ts to version 1.2

From dexie.js source repo commit 92372b017810704bd7f812e7b0b86df866e8d222
--
Allow dexie to be referenced in typescript projects.
e.g.

```
import * as Dexie from 'dexie';
```

Dexie will now be properly typed without having to reference Dexie.d.ts in DefinitelyTyped or through src/Dexie.d.ts (which isn't exposed in npm anyways)
Penryn/DefinitelyTyped,nycdotnet/DefinitelyTyped,trystanclarke/DefinitelyTyped,pwelter34/DefinitelyTyped,ashwinr/DefinitelyTyped,UzEE/DefinitelyTyped,musicist288/DefinitelyTyped,benishouga/DefinitelyTyped,greglo/DefinitelyTyped,donnut/DefinitelyTyped,rcchen/DefinitelyTyped,Softpagehomeware/DefinitelyTyped,subash-a/DefinitelyTyped,jraymakers/DefinitelyTyped,UzEE/DefinitelyTyped,nainslie/DefinitelyTyped,trystanclarke/DefinitelyTyped,EnableSoftware/DefinitelyTyped,jraymakers/DefinitelyTyped,DzmitryDulko/DefinitelyTyped,use-strict/DefinitelyTyped,georgemarshall/DefinitelyTyped,Softpagehomeware/DefinitelyTyped,dsebastien/DefinitelyTyped,magny/DefinitelyTyped,gandjustas/DefinitelyTyped,shlomiassaf/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,abbasmhd/DefinitelyTyped,HPFOD/DefinitelyTyped,raijinsetsu/DefinitelyTyped,Penryn/DefinitelyTyped,zuzusik/DefinitelyTyped,pocesar/DefinitelyTyped,frogcjn/DefinitelyTyped,jimthedev/DefinitelyTyped,nfriend/DefinitelyTyped,YousefED/DefinitelyTyped,nakakura/DefinitelyTyped,dsebastien/DefinitelyTyped,aciccarello/DefinitelyTyped,florentpoujol/DefinitelyTyped,donnut/DefinitelyTyped,frogcjn/DefinitelyTyped,smrq/DefinitelyTyped,martinduparc/DefinitelyTyped,arusakov/DefinitelyTyped,one-pieces/DefinitelyTyped,psnider/DefinitelyTyped,rcchen/DefinitelyTyped,benliddicott/DefinitelyTyped,amanmahajan7/DefinitelyTyped,MugeSo/DefinitelyTyped,georgemarshall/DefinitelyTyped,ryan-codingintrigue/DefinitelyTyped,emanuelhp/DefinitelyTyped,borisyankov/DefinitelyTyped,smrq/DefinitelyTyped,psnider/DefinitelyTyped,ryan10132/DefinitelyTyped,MugeSo/DefinitelyTyped,borisyankov/DefinitelyTyped,aciccarello/DefinitelyTyped,slavomirvojacek/DefinitelyTyped,nitintutlani/DefinitelyTyped,chrismbarr/DefinitelyTyped,amir-arad/DefinitelyTyped,scriby/DefinitelyTyped,wilfrem/DefinitelyTyped,newclear/DefinitelyTyped,mhegazy/DefinitelyTyped,EnableSoftware/DefinitelyTyped,chrootsu/DefinitelyTyped,johan-gorter/DefinitelyTyped,hellopao/DefinitelyTyped,ashwinr/DefinitelyTyped,Zzzen/DefinitelyTyped,OpenMaths/DefinitelyTyped,wilfrem/DefinitelyTyped,slavomirvojacek/DefinitelyTyped,paulmorphy/DefinitelyTyped,alvarorahul/DefinitelyTyped,nobuoka/DefinitelyTyped,minodisk/DefinitelyTyped,alexdresko/DefinitelyTyped,eugenpodaru/DefinitelyTyped,xStrom/DefinitelyTyped,shlomiassaf/DefinitelyTyped,chrootsu/DefinitelyTyped,benishouga/DefinitelyTyped,florentpoujol/DefinitelyTyped,magny/DefinitelyTyped,gcastre/DefinitelyTyped,slavomirvojacek/adbrain-typescript-definitions,Pro/DefinitelyTyped,jimthedev/DefinitelyTyped,minodisk/DefinitelyTyped,QuatroCode/DefinitelyTyped,syuilo/DefinitelyTyped,raijinsetsu/DefinitelyTyped,reppners/DefinitelyTyped,chrismbarr/DefinitelyTyped,CodeZombieCH/DefinitelyTyped,aciccarello/DefinitelyTyped,Dashlane/DefinitelyTyped,jimthedev/DefinitelyTyped,schmuli/DefinitelyTyped,georgemarshall/DefinitelyTyped,flyfishMT/DefinitelyTyped,amanmahajan7/DefinitelyTyped,paulmorphy/DefinitelyTyped,GiedriusGrabauskas/DefinitelyTyped,sclausen/DefinitelyTyped,johan-gorter/DefinitelyTyped,axelcostaspena/DefinitelyTyped,martinduparc/DefinitelyTyped,laurentiustamate94/DefinitelyTyped,chbrown/DefinitelyTyped,nitintutlani/DefinitelyTyped,mattblang/DefinitelyTyped,micurs/DefinitelyTyped,Zzzen/DefinitelyTyped,subash-a/DefinitelyTyped,mcrawshaw/DefinitelyTyped,vagarenko/DefinitelyTyped,nycdotnet/DefinitelyTyped,mareek/DefinitelyTyped,AgentME/DefinitelyTyped,GiedriusGrabauskas/DefinitelyTyped,tan9/DefinitelyTyped,scriby/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,damianog/DefinitelyTyped,philippstucki/DefinitelyTyped,alexdresko/DefinitelyTyped,QuatroCode/DefinitelyTyped,zuzusik/DefinitelyTyped,arusakov/DefinitelyTyped,sledorze/DefinitelyTyped,stephenjelfs/DefinitelyTyped,stephenjelfs/DefinitelyTyped,markogresak/DefinitelyTyped,Ptival/DefinitelyTyped,HPFOD/DefinitelyTyped,arma-gast/DefinitelyTyped,mcrawshaw/DefinitelyTyped,tan9/DefinitelyTyped,reppners/DefinitelyTyped,yuit/DefinitelyTyped,flyfishMT/DefinitelyTyped,rolandzwaga/DefinitelyTyped,pwelter34/DefinitelyTyped,AgentME/DefinitelyTyped,newclear/DefinitelyTyped,isman-usoh/DefinitelyTyped,Litee/DefinitelyTyped,DzmitryDulko/DefinitelyTyped,Pro/DefinitelyTyped,Dashlane/DefinitelyTyped,rolandzwaga/DefinitelyTyped,nakakura/DefinitelyTyped,mhegazy/DefinitelyTyped,hellopao/DefinitelyTyped,emanuelhp/DefinitelyTyped,arusakov/DefinitelyTyped,sledorze/DefinitelyTyped,slavomirvojacek/adbrain-typescript-definitions,benishouga/DefinitelyTyped,isman-usoh/DefinitelyTyped,xStrom/DefinitelyTyped,danfma/DefinitelyTyped,schmuli/DefinitelyTyped,mattblang/DefinitelyTyped,pocesar/DefinitelyTyped,stacktracejs/DefinitelyTyped,AgentME/DefinitelyTyped,use-strict/DefinitelyTyped,Litee/DefinitelyTyped,progre/DefinitelyTyped,progre/DefinitelyTyped,abner/DefinitelyTyped,abbasmhd/DefinitelyTyped,stacktracejs/DefinitelyTyped,YousefED/DefinitelyTyped,danfma/DefinitelyTyped,philippstucki/DefinitelyTyped,psnider/DefinitelyTyped,arma-gast/DefinitelyTyped,georgemarshall/DefinitelyTyped,abner/DefinitelyTyped,vagarenko/DefinitelyTyped,hellopao/DefinitelyTyped,mcliment/DefinitelyTyped,zuzusik/DefinitelyTyped,OpenMaths/DefinitelyTyped,martinduparc/DefinitelyTyped,syuilo/DefinitelyTyped,CodeZombieCH/DefinitelyTyped,yuit/DefinitelyTyped,damianog/DefinitelyTyped,AgentME/DefinitelyTyped,pocesar/DefinitelyTyped,mareek/DefinitelyTyped,Ptival/DefinitelyTyped,sclausen/DefinitelyTyped,nobuoka/DefinitelyTyped,alvarorahul/DefinitelyTyped,schmuli/DefinitelyTyped,gandjustas/DefinitelyTyped,gcastre/DefinitelyTyped,daptiv/DefinitelyTyped,nainslie/DefinitelyTyped,greglo/DefinitelyTyped