You can stop merge keeping all current changes in the working directory using stash. Witch stops the on going merge automatically.
Revision control, also known as version control and source control (and an aspect of software configuration management), is the management of changes to documents, computer programs, large web sites, and other collections of information. Changes are usually identified by a number or letter code, termed the "revision number", "revision level", or simply "revision". Each revision is associated with a timestamp and the person making the change. Revisions can be compared, restored, and with some types of files, merged.