Allow specifying base path

[dominics]

We've just migrated our CI system to one that uses build artifacting. As a consequence, when we run our unit tests, we're no longer doing so within a Git repository.

Most of UploadCommand is careful not to assume the current dir is a repository, and we can specify --repository, --parent and --revision manually. However, the ->getBasePath() call assumes one of the parents of the working directory will have a .git directory (here: https://github.com/scrutinizer-ci/ocular/blob/master/src/Scrutinizer/Ocular/Command/CodeCoverage/UploadCommand.php#L106) and there's no way to override this strategy.

[rafaelmagu]

In addition to the above, it seems that if .git is missing, UploadCommand goes into a never-ending loop. An strace session shows the following:

(...)
gettimeofday({1424730444, 280526}, NULL) = 0
gettimeofday({1424730444, 280601}, NULL) = 0
stat("//.git", 0x7fff18fefcf0)          = -1 ENOENT (No such file or directory)
gettimeofday({1424730444, 280752}, NULL) = 0
gettimeofday({1424730444, 280828}, NULL) = 0
stat("//.git", 0x7fff18fefcf0)          = -1 ENOENT (No such file or directory)
gettimeofday({1424730444, 280976}, NULL) = 0
gettimeofday({1424730444, 281050}, NULL) = 0
stat("//.git", 0x7fff18fefcf0)          = -1 ENOENT (No such file or directory)
gettimeofday({1424730444, 281196}, NULL) = 0
gettimeofday({1424730444, 281272}, NULL) = 0
stat("//.git", 0x7fff18fefcf0)          = -1 ENOENT (No such file or directory)
gettimeofday({1424730444, 281419}, NULL) = 0
gettimeofday({1424730444, 281493}, NULL) = 0
stat("//.git", 0x7fff18fefcf0)          = -1 ENOENT (No such file or directory)
gettimeofday({1424730444, 281646}, NULL) = 0
gettimeofday({1424730444, 281728}, NULL) = 0
(...)