Fixed slashed ignore pattern.
Fixed a bug that dosen't work slashed ignore pattern in sub directory's gitignore file.
Fixed a bug that dosen't work slashed ignore pattern when specified path.
Fixed a bug that mismatch ignore pattern when exists multiple gitignore and same directory struct.
Removed unnecessary match function argument.
Added a test that exist subdirectory gitignore and same directory struct.
Fixed a bug that happens panic when use global gitignore.
Fixed a bug that subdirectory gitignore dosen't work with specified path.
Removed unnecessary gitignore depth parameter.
Merge pull request #61 from monochromegane/fix-gitignore-bugs

Fix bugs of parsing gitignore
Bumped version to 1.7.5.
Fix git ignore depth