Optimize plugin version checking when update intellij platform version

[shlxue]

Merge remote-tracking branch 'JetBrains/master', and update #228.

Checking plugin version by plugin version and since build

@alexeypegov @ignatov

[klikh]

Could you please rebase the branch onto master and remove the "Merge pull request #1" commit, leaving only the meaningful one. Thanks!

[shlxue]

Sorry, I removed it. Now: the plugin version will be find when idea platform upgraded, but downgrade don't.

@klikh