Merge pull request #201 from mewoch/man2-2

Man2 2
corrected description of update preview
Merging new training manual into master
linking to training manual
cleanup (big one)
update whats new for 2.2 release
Merge branch 'master' of github.com:qgis/QGIS-Documentation
update release version to 2.2
Add diagram with expression documentation
Update plugins.rst

The page was not referring to the Quantum Gis version it was supposed to be referring to, was inaccurate and confusing. Now it is a little bit better, but further work is needed.
Most important changes refer to __init__.py and classFactory
Merge pull request #205 from nydydn/patch-1

Update plugins.rst making text better correspond to current plugin situation
Merge pull request #204 from sbrunner/expression

Add diagram with expression documentation
update from Jiri Kadlec
style fixes from QGIS-Website
footer fix
reuse sphinx bootstrap theme js
[Py QGIS cookbook] Debugging Vector Layers

QgsGeometry has no vectorType but a type method
processing has no getfeatures but a features method
Vector layer has a selectedFeatures method to accessing only selected
features.
adding training manual to pdf build
forgot copystep to live dir
fix #208

all :numbered: stuff removed, so numbering is back to normal