Update FindPkgConfig.cmake sha1sum

Fixes #59
Update FindPkgConfig
YCMEPHelper: Add developer mode

Each subproject now has a YCM_EP_DEVEL_MODE_<Proj> cached variable that
is used to enable devel mode targets and disable the update target.

The YCM_EP_EXPERT_MODE enables the update targets for the projects in
development mode.

The YCM_EP_MAINTAINER_MODE enables all the targets for all the projects.

Fixes #31
Add more docs, re-license to 3-clause BSD, and fix missing licenses

Also update sha1sums.

Fixes #33
CC-Issue #46
gen-gh-pages.sh: Run "make documentation" target only instead of "all"
Generate documentation