README: update
README: update

- Add exposition on why Nimble is useful
- Include Swift and Objective-C examples for all matchers
- Better installation instructions
- Update code samples to include scope modifiers like `public`

msdgwzhy6/Nimble,feinstruktur/Nimble,alexbasson/Nimble,abbeycode/Nimble,Quick/Nimble,phatblat/Nimble,nikita-leonov/Nimble,rbeeger/Nimble,gfontenot/Nimble,briancroom/Nimble,gfontenot/Nimble,ScottRobbins/Nimble,rbeeger/Nimble,joemasilotti/Nimble,rbeeger/Nimble,abbeycode/Nimble,twobitlabs/Nimble,octo-technology/Nimble,octo-technology/Nimble,msdgwzhy6/Nimble,alvinvarghese/Nimble,mrackwitz/Nimble,mrackwitz/Nimble,jrmiddle/Nimble,abbeycode/Nimble,DanielAsher/Nimble,Quick/Nimble,mrackwitz/Nimble,nikita-leonov/Nimble,romankl/Nimble,ashfurrow/Nimble,mishimay/Nimble,ashfurrow/Nimble,alvinvarghese/Nimble,jrmiddle/Nimble,NatashaTheRobot/Nimble,feinstruktur/Nimble,vtongcoder/Nimble,makezwl/zhao,mishimay/Nimble,romankl/Nimble,jeffh/Nimble,gfontenot/Nimble,jeffh/Nimble,dgdosen/Nimble,jrmiddle/Nimble,AnthonyMDev/Nimble,alexbasson/Nimble,mrackwitz/Nimble,nikita-leonov/Nimble,phatblat/Nimble,joemasilotti/Nimble,twobitlabs/Nimble,dgdosen/Nimble,AnthonyMDev/Nimble,briancroom/Nimble,makezwl/zhao,octo-technology/Nimble,briancroom/Nimble,github/Nimble,alvinvarghese/Nimble,dgdosen/Nimble,joemasilotti/Nimble,feinstruktur/Nimble,Quick/Nimble,alvinvarghese/Nimble,ashfurrow/Nimble,abbeycode/Nimble,DanielAsher/Nimble,romankl/Nimble,ScottRobbins/Nimble,NatashaTheRobot/Nimble,rbeeger/Nimble,msdgwzhy6/Nimble,jeffh/Nimble,jeffh/Nimble,alexbasson/Nimble,twobitlabs/Nimble,github/Nimble,msdgwzhy6/Nimble,NatashaTheRobot/Nimble,mishimay/Nimble,vtongcoder/Nimble,romankl/Nimble,gfontenot/Nimble,vtongcoder/Nimble,briancroom/Nimble,dgdosen/Nimble,AnthonyMDev/Nimble,ScottRobbins/Nimble,alexbasson/Nimble,makezwl/zhao,phatblat/Nimble,octo-technology/Nimble,DanielAsher/Nimble,NatashaTheRobot/Nimble,jrmiddle/Nimble