[Azoth MuC] Moved ListUrls() and OpenUrl() to separate .cpp.

Also, return StringCommandResult from ListUrls().

For #1752, for #1753, for #1754.
[Azoth MuC] Renamed CommandsTest to PresenceCommandTest.

More are coming.
[Azoth MuC] Moved pretty-printing boost::variants to testutil.h.
[Azoth MuC] AddMuCTest macro for tests.
[Azoth MuC] More generic var printer in TestUtil.
[Azoth MuC] OpenUrl parser stubs.

For #1752, for #1753, for #1754.
[Azoth MuC] Somewhat implemented qi openurl parser.

For #1752, for #1753, for #1754.
[Azoth MuC] Added openurl tests stub.

For #1752, for #1753, for #1754.
[Azoth MuC] Added range commands tests.

For #1752, for #1753, for #1754.
Revert "[Azoth MuC] More generic var printer in TestUtil."

This reverts commit 8acdb1de7b2cef72db5c835eb5b71b76577bcfe0.
[Azoth MuC] Moved toString() for Status_t to the test file.
[Azoth MuC] Fixed rx rule.
[Azoth MuC] OpenUrlParams_t is printable now.
[Azoth MuC] Added rx tests.