vala.m4: Add VALA_CHECK_MODULES and VALA_PROG_VAPIGEN

Fixes bug 642301.
Add support for [Profile] method attribute

This allows simple method-level profiling. Requires GCC.
posix: Add stat fields for high precision access/modification/status change timestamps (POSIX.1-2008)
glib-2.0: Use correct GTest*Func bindings on GLib >= 2.26
glib-2.0: Update GUnicodeScript and GUnicodeBreakType bindings

Fixes bug 674660.
codegen: Fix profiling for recursive methods
Release 0.17.0
glib-2.0: Move Unicode* and NormalizeMode enums under GLib

Fixes bug 675082.
Use correct variable name to add vapigen directories

Fixes bug 675097.
posix: add execv(p) and sigqueue methods, make sigval_t a simple type

Fixes bug 673391.
gsl: correct MultifitLinearWorkspace construct/free C names

Fixes bug 670838.
rest-0.7: update to git master

Fixes bug 670488.
gio-2.0: update to git master
gio-2.0: set error domain in metadata instead of custom vala

Fixes bug 669497.
gobject-2.0: add Type.{get,set}_qdata methods

Fixes bug 673392.
glib-2.0: add Hmac bindings

Fixes bug 670243.
gtk+-2.0, gtk+-3.0: make TextTag constructor's parameter nullable
build: Note that we don't support srcdir != builddir
build: Fix regression in previous commit
posix: Add parse and to_string methods and string.printf

Fixes bug 666436.