Extract full text in `content_plain` using jquery.

Gmail will give only a part of plain text. However we can extract complete text using jquery `.text()` method
Merge remote-tracking branch 'upstream/master'
Merge pull request #73 from madhugb/master

Extract full text in `content_plain` using jQuery.
Added Dutch dictionary to api.tools.i18n
Merge pull request #74 from vijnv/patch-1

Added Dutch dictionary to api.tools.i18n
Added CSP details to readme #75
Removed DOM observers documentation
Update gmail.min.js
Merge pull request #76 from GabrielDuque/patch-1

Update gmail.min.js
Update gmail.min.js
Merge pull request #77 from GabrielDuque/patch-2

Update gmail.min.js
Added condition to prevent functions from being parsed.
Moved the continue in new line
Merge pull request #79 from sonnyt/master

Added condition to prevent functions from being parsed.
api.get.compose_id() now compatible with full screen #78
Merge pull request #80 from KartikTalwar/compose-id-fullscreen

api.get.compose_id() now compatible with full screen
Update gmail.min.js
Check if VIEW_DATA is defined, if not set as empty array
Removed DOM observers docs
If 'to' field is undefined then fetch it from 37th index