Unconditionnally include oce-config.h in header files

Fix issue #478.
Re-add math defines for MinGW

Commit 5c79896 took away the math defines, these defines are needed under MinGW if strict ANSI compilation is performed
Reverted removal 'get_target_property' to discover ARCHIVE_OUTPUT_DIRECTORY.

If 'CMAKE_ARCHIVE_OUTPUT_DIRECTORY' is used to customize the output
folders of oce-win-bundle libraries, the oce build will set
FREETYPE_LIBRARY and related variables to the wrong paths.

This patch fixes that bug.

The commit that inserted this removal in the first place
(https://github.com/tpaviot/oce/pull/465) did not provide any explination
for it.
ApproxAFunc2Var: numerical bug triggered by compiler optimization

Here Result and Constraints UpdateInX method expect exactly the same value.
Because of the compiler optimization the evaluation of
myFirstParInU+iint*deltu may be different between Result and Constraints
update call.
Merge pull request #479 from tpaviot/review/unconditionnally-include-oce-config.h

Unconditionnally include oce-config.h in header files
Merge pull request #481 from tpaviot/review/mingw-math-defines

Re-add math defines for MinGW
Merge pull request #482 from camio/revert-get_target_property-removal

Revert get target property removal
Merge pull request #486 from jeromerobert/ApproxAFunc2Var_gcc_optim_bug

ApproxAFunc2Var: numerical bug triggered by compiler optimization
Revert "Removed OCE_DISABLE_TKSERVICE_FONT"

(This reverts commit a016096d4559bd601d96863f56f4afd4242c469c.)
Updated to work with latest version of OCE by adding a couple of
ifdef's in AIS/AIS_Dimension.cxx.