This commit splits the PLTs into 2, one for all the required OTP
applications that are in the stdlib, and the other for the rebar
dependancies. Each one is created if it does not exist, then checked for
validity and then --add_to_plt is used to add any missing files (this is
very fast if nothing needs to be added). Then the application is
dialyzed using both PLTs.

The 'combo' PLT which resides in ~ is intended to be used by all of
Riak's deps, so it can grow to cover the set of OTP applications that
Riak depends on. Each project can only specify the ones it cares about.

Adds transparent event stream processing and statistics.
A new 3-tuple trace is introduced as `{Key, Op, Value}`, but
for backwards compatibility `{Key, Val}` implies `=` for `Op`
and `{Key, '*'}` remains as is in the case of wildcards.
A simplified query tree module is generated which reduces
redundant selection conditions to minimize filtering overhead.

This also removes the dependency on the syntax_tools and compiler
applications, which interfered with lager's startup/shutdown order.