Integrate kdev-perforce into kdevelop

Summary:

This plugin facilitates integration with the perforce version control system

It supports:

Adding files to a perforce repository
Opening a file for edit
Reverting changes made to a file
Updating a file to the latest version (head) in the repository
Listing the change history of a files
Comparing a file to latest verion (head)
Comparing a file to the version that a given perforce client has checked out (have revision)
Comparing any given two revisions (through the history)
Annotating a file (i.e. telling from which changelist a given line of code came from )

Test Plan:

The following use-cases are currently under unit-test:

Add,Edit,Status,Annotate,History,Revert,Update(File),Update(Dir),Commit

Manually tested against Perforce servers

Reviewers: #kdevelop, kfunk

Reviewed By: #kdevelop, kfunk

Subscribers: kdevelop-devel

Differential Revision: https://phabricator.kde.org/D2001