Update landing page

Add "Start now" section right under the buttons and left to the logo so
that guys can start with compound with reading any stuff
change why, what, how with "what is under the hood" since chemistry is
in the Logo
started with new generators structure
app generator
Docs renamed to sources
Update extensions API
Some basic compound api docs
Merge pull request #1 from anatoliychakkaev/master

docs for review - extensions api
minor app generator fixes
removed weird characters
Fixes from mans
added model generator class, fixed app name when no argument is given
finished model generator
nice renaming
moved scaffold templates to compound project, generating crud templates and helpers
removed templates
AppGenerator: correctly generate database.{json|yml}
Routing documentation
Removed bullshit from indexhtml
properly generating templates
fixed js application controller