Fixes #415 - branch names mangled by color escapes

- add "-c color.branch=never" option to git branch commands, definitively disabling color branch output

.# Discussion

Branch names are mis-parsed if `git branch` output is colored (eg, when git is configured
with "config.branch=always"). Using the base "-c color.branch=never" option overrides any
user configuration, displaying git branch output as uncolored in all cases and fixing the
issue.

Notably, option ordering is important in this instance. The "-c ..." option is a git
base option, not a git branch subcommand option. So, as done here, it must be inserted
before the "branch" subcommand.

ref: Issue #415

src/git/git.ts

@@ -325,7 +325,7 @@ export class Git {
     }
 
     static branch(repoPath: string, options: { all: boolean } = { all: false }) {
-        const params = ['branch', '-vv'];
+        const params = ['-c', 'color.branch=never', 'branch', '-vv'];
         if (options.all) {
             params.push('-a');
         }
@@ -334,7 +334,7 @@ export class Git {
     }
 
     static branch_contains(repoPath: string, ref: string, options: { remote: boolean } = { remote: false }) {
-        const params = ['branch', '--contains'];
+        const params = ['-c', 'color.branch=never', 'branch', '--contains'];
         if (options.remote) {
             params.push('-r');
         }