[CMake] Guidance in FindwxWidgets commit submission.

[Miguel A. Figueroa-Villanueva]

<Bill, I'm sending this directly to you, since this is the first cvs
commit that I'll be doing and would like to make sure that it is all
ok. Sorry, if this is inappropriate.>

Hello,

As its maintainer, I'm almost done in testing the locally updated
FindwxWidgets. I've cleaned up a few things, added support for some
issues in the bug tracker and deprecated some things.

Before I commit, I would like to make sure I did the right thing in
the following things (to avoid having to roll-back):

1. There is a work-around to support wxWidgets_FIND_COMPONENTS in
cmake-2.4.2. I have removed this since this will be released in
cmake-2.4.7+ Is this appropriate?

2. I deprecated the use of wxWidgets_USE_LIBS in favor of doing

FIND_PACKAGE(wxWidgets REQUIRED core base gl)

rather than

SET(wxWidgets_USE_LIBS core base gl)
FIND_PACKAGE(wxWidgets)

wxWidgets_USE_LIBS will still be supported for backward compatibility,
but not documented in the help message.

3. I changed EXEC_PROGRAM in favor of EXECUTE_PROCESS.

4. I changed STRING(REGEX REPLACE ...) in favor of STRING(REPLACE
...). I believe the latter was not available at the time of writing
the FindwxWidgets, but I don't see a reason to not use it now. I'm
also using SEPARATE_ARGUMENTS(...), where there was STRING(REGEX
REPLACE " " ";" ...).

5. I'm using LIST(FIND ...) command in the code. Again is this
appropriate? Note that LIST(FIND ...) is a very recent addition (5
weeks ago)? I can avoid it, it just doesn't make sense if this is
being released at the time that LIST(FIND ...) will be available.

6. Using STRING(STRIP ...). Note that this was added 5 months ago...

7. I also added the aui library and wxWidgets-2.8.5 support.

Looking forward to some feedback.

--Miguel