[issue #1] missing min files in dist

The bowerDist task does not copy the min files to the dist folder. Now
they are picked up as expected.
Merge branch 'bug/1-missing-minified-files' into dev
[issue #2] proper timestamp handling on fail

The checkDependencies task wrote the lastCheck time every time even if the
task actually failed. The reason is that grunt does NOT stop immediately
on fatal/warn as stated in doc but finishes the "surrounding" task. We
have to check manually if the install task went properly.
Merge branch 'bug/2-proper-timestamp-on-dependency-check' into dev