Add script to update sha1sums
Use YCM as project name
YCMBootstrap: Do not use set_package_properties if FeatureSummary was not included
Allow to override parameters used by ycm_ep_helper by setting variables

The variables are in the form <NAME>_<PARAMETER>

Fixes #4 (override using <NAME>_CMAKE_ARGS and/or <NAME>_CMAKE_CACHE_ARGS)
Fixes #5 (override using <NAME>_TAG for git or <NAME>_REVISION for svn)
Fixes #6 (override using <NAME>_STYLE and <NAME>_REPOSITORY)