Fixed a few bugs in wildcard matching.

Wildcards are anchored, unlike regexes. Furthermore, ? in a wildcard
always matches a single character, not at most one character.

Added tests as well.
Resolved some warnings.
Fixed FileSystemProvider behavior with relative path
Merge pull request #242 from sburnicki/newitem_fix

Fixed FileSystemProvider behavior with relative path
Merge pull request #241 from sburnicki/removed_warnings

Resolved some warnings
TEST: Fix Add-Type tests on other locales.
Merge pull request #246 from mrward/fix-add-type-command-tests

TEST: Fix Add-Type tests on other locales.
Merge pull request #238 from ygra/wildcard-anchor

Fixed a few bugs in wildcard matching.