Locks: Replace global Item list by a local Red Black Tree
Fix Windows build.

Windows has the BUILTIN_EXTENSIONS define set, but we tried to use
different defines for each possible plugin. Revert to using one single
define for all plugins, which will make Windows skip the code related
to plugin loading.
Merge pull request #935 from kacfengine/master

Fix Windows build.
Merge pull request #936 from tzz/tzz/2516-numeric-sort

Add example of using sort()
Make Rlist a list of Rvals
Add EvalContextVariableTags
Merge pull request #912 from lpefferkorn/speedup0

Redmine #1875: Locks - Replace global Item list by a local Red Black Tree
Remove negated class heap.
Redmine#2111: eval() function for math evaluation
Redmine#2111: Bring in peg 0.13 under 3rdparty/