[Sys.Data] Add unit tests for Novell bug #519648

These unit tests demonstrate the difference to .NET
(https://bugzilla.novell.com/show_bug.cgi?id=519648).
[Sys.Data] Fix Novell Bug #519648

Don't throw an exception when passing "new object[] {null}" to
DataRowCollection.Find. This makes the behaviour more compatible
with .NET. This fixes bug #519648
(https://bugzilla.novell.com/show_bug.cgi?id=519648).
[System.XML] Add unit test for #18118
[System.XML] Fix handling of global variables in XSLs (#18118)
[System.XML] Add unit test for XSL note-set bug (#18114)
[System.XML] Fix XSL node-set bug (#18114)

XSL node-set function now behaves more like MS version.
[System.XML] Add unit test for XSL value-of bug (#18113)
[System.XML] Fix handling of space in XSL value-of elements (#18113)
[Fix] Bugzilla #18213 - System.Runtime.Caching.MemoryCache doesn't honor SlidingExpiration
Merge pull request #961 from ermshiperete/bug-xamarin-18118

[System.XML] XSL bugfixes for #18118 #18114 #18113
[genproj] For Path.GetFullPath to work, we must use convert Windows paths to Unix paths
genproj: add support for Alias in project references
Revert "[counters] Simplify things a bit by removing unsigned counter types."

This reverts commit 2fa83d9a8cef9d5a5c050e40bc2f757dba445997.
[mono-counters] Bring MONO_COUNTER_TIME_INTERVAL back.
[counters] Install mono-counters.h since it's part of the public API.
[counters] Document mono_counters_foreach.
[counters] Restore the previous behavior of mono_counters_dump, add variance filtering and reorg the bitfield.

The previous behavior when using mono_counters_dump was to pass -1 as the section and get all
counters dumped. This commit restore this behavior.

In addition to that, we want to enable callers to filter by variance as non monotonic counters are not useful
to be dumped at shutdown. To do so you just OR the variance with the sections you want. So what the runtime wants is:

	mono_counters_dump (MONO_COUNTER_SECTION_MASK | MONO_COUNTER_MONOTONIC, stdout);

Dump all counters that are monotonic. Perfect.

Finally, to make the above neat, a reorg of the type bitfield was needed. Variance is now using a bit per kind.
Variance and unit where shrunk to 4 bits each, to open space for more sections.
[counters] Only dump monotonic counters as variable ones are meaningless during shutdown.
Drop Events and Items units in favor of Count as they represent pretty much the same thing.
Extended test time for timer-sensitive tests.