Trim leading whitespace from branch names

For branches other than the current branch, there is leading whitespace which was not trimmed. The current branch was alright since it was handled by the removal of "*".  Example of the test run before the fix:

````
[dmayo@nc1lt3842b PHP-Stream-Wrapper-for-Git]$ vendor/phpunit/phpunit/phpunit.php tests
PHPUnit 3.7.34 by Sebastian Bergmann.

Configuration read from /home/dmayo/Repos/PHP-Stream-Wrapper-for-Git/phpunit.xml.dist

............F..................................................  63 / 250 ( 25%)
............................................................... 126 / 250 ( 50%)
............................................................... 189 / 250 ( 75%)
.............................................................

Time: 1.06 minutes, Memory: 9.25Mb

There was 1 failure:

1) TQ\Tests\Git\Repository\InfoTest::testGetBranches
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
     0 => 'master'
-    1 => 'x-feature'
+    1 => '  x-feature'
 )

/home/dmayo/Repos/PHP-Stream-Wrapper-for-Git/tests/TQ/Tests/Git/Repository/InfoTest.php:87

FAILURES!
Tests: 250, Assertions: 1528, Failures: 1.