Fixed a bug in the compilation error regular expression

Errors are sometimes reported with "Error:" and then a newline, but the
regular expression was only looking for a normal space ("Error: ")
Moved the PIDE error extraction code to a new utility function
Also print errors when the PIDE Coq editor's caret moves
Added shortcuts to the Coq file and project wizards to the Coq perspective
Updated the embedded snapshot of PIDE
Bumped the version numbers to 0.4.6.1 and added a changelog entry