Improve docstring for 'save' method and others.
Improve docstring for 'save' method and others.

I encountered some confusion recently when I was trying out the 'save' functionality for models. I have adjusted the relevant documentation to provide a more detailed reflection of the current functionality and intent of the method. I have also replaced the use of varying terminology ('experiment', 'model', 'model checkpoint') with 'model' alone, for simplicity and clarity.

While I'm here, I have also made minor adjustments to the other docstrings in the file for overall consistency, in line with suggested Python style:

"The docstring is a phrase ending in a period. It prescribes the function or method's effect as a command ("Do this", "Return that"), not as a description; e.g. don't write "Returns the pathname ..."."
lscheinkman/nupic,badlogicmanpreet/nupic,numenta/nupic,sambitgaan/nupic,brev/nupic,GeraldLoeffler/nupic,vitaly-krugl/nupic,scottpurdy/nupic,virneo/nupic,pulinagrawal/nupic,cogmission/nupic,EricSB/nupic,vamsirajendra/nupic,lscheinkman/nupic,markneville/nupic,akhilaananthram/nupic,rcrowder/nupic,fergalbyrne/nupic,arhik/nupic,subutai/nupic,rhyolight/nupic,wanghaven/nupic,darshanthaker/nupic,rhyolight/nupic,BeiLuoShiMen/nupic,neuroidss/nupic,chanceraine/nupic,GeraldLoeffler/nupic,numenta-ci/nupic,pap/nupic,lscheinkman/nupic,rcrowder/nupic,pulinagrawal/nupic,darshanthaker/nupic,rayNymous/nupic,scottpurdy/nupic,marionleborgne/nupic,glorizen/nupic,chen0031/nupic,rayNymous/nupic,elkingtonmcb/nupic,vamsirajendra/nupic,breznak/nupic,wanghaven/nupic,akhilaananthram/nupic,chen0031/nupic,SaganBolliger/nupic,fergalbyrne/nupic,alfonsokim/nupic,BoltzmannBrain/nupic,cngo-github/nupic,blueburningcoder/nupic,passiweinberger/nupic,metaml/nupic,chanceraine/nupic,badlogicmanpreet/nupic,breznak/nupic,elkingtonmcb/nupic,sambitgaan/nupic,mcanthony/nupic,metaml/nupic,allanino/nupic,go-bears/nupic,GeraldLoeffler/nupic,mcanthony/nupic,elkingtonmcb/nupic,ben-hopps/nupic,subutai/nupic,ben-hopps/nupic,alfonsokim/nupic,cogmission/nupic,runt18/nupic,vitaly-krugl/nupic,eranchetz/nupic,passiweinberger/nupic,markneville/nupic,wanghaven/nupic,glorizen/nupic,metaml/nupic,go-bears/nupic,sambitgaan/nupic,numenta/nupic,alfonsokim/nupic,loretoparisi/nupic,vamsirajendra/nupic,blueburningcoder/nupic,SaganBolliger/nupic,eranchetz/nupic,subutai/nupic,BeiLuoShiMen/nupic,BoltzmannBrain/nupic,ywcui1990/nupic,marionleborgne/nupic,cngo-github/nupic,cngo-github/nupic,mcanthony/nupic,rhyolight/nupic,loretoparisi/nupic,ywcui1990/nupic,chanceraine/nupic,virneo/nupic,numenta-ci/nupic,ywcui1990/nupic,BoltzmannBrain/nupic,rayNymous/nupic,allanino/nupic,rcrowder/nupic,pap/nupic,SaganBolliger/nupic,numenta-ci/nupic,brev/nupic,numenta/nupic,allanino/nupic,neuroidss/nupic,passiweinberger/nupic,akhilaananthram/nupic,ben-hopps/nupic,pulinagrawal/nupic,jcasner/nupic,eranchetz/nupic,arhik/nupic,runt18/nupic,marionleborgne/nupic,pap/nupic,chen0031/nupic,go-bears/nupic,markneville/nupic,vitaly-krugl/nupic,brev/nupic,blueburningcoder/nupic,breznak/nupic,glorizen/nupic,EricSB/nupic,arhik/nupic,badlogicmanpreet/nupic,darshanthaker/nupic,fergalbyrne/nupic,runt18/nupic,cogmission/nupic,scottpurdy/nupic,jcasner/nupic,jcasner/nupic,neuroidss/nupic,BeiLuoShiMen/nupic,EricSB/nupic,virneo/nupic,loretoparisi/nupic