Add method to atom to calculate Lewis acid/base vacancies
Add method to molecule to convert zero-order bonds to single or double bounds and adjust adjacent charges accordingly.
Add ZBO, ZCH, HYD extensions to MDL format
Stop AddHydrogens from resetting the ImplicitValencePerceived flag
Fix bug where unnecessary HYD values were written in MDL format
Remove leftover logging statements
Fix indentation
Moved the C99 support headers to windows-msvc

The C99 support headers do not need any library, and should work with
any version of MSVC, whereas the xdr and cairo headers are tied to a
particular version of some libraries that are paired with binary
prebuild libraries.

It should now be possible to build on any MSVC toolchain if all
dependencies are built correctly.
Merge remote-tracking branch 'upstream/master' into mdlextension
Made the CairoPainter object a private variable to the class again instead of a local var in WriteMolecule(). I got errors when trying to depict multiple molecules otherwise.
Made hash bonds draw with line width 1, required adding the function GetPenWidth to the different painters to be able to reset the pen width after drawing the bond.
Added the -b and -B options to pngformat to allow changes of colors when creating pngs.
Added -xm option for possibility to "crop" output image to a close bounding box of a single molecule.
Changed the metrics calculation in cairopainter to give nicer layout of text labels with sub and superscripts.
Merge pull request #22 from cryos/windows-inttypes

Moved the C99 support headers to windows-msvc
Improve space group support in .car files

- Support Hermann-Mauguin notation space groups with spaces and also
  the unspecified default space group.

- HM space group is enclosed within parentheses and can contain space
  between them as per the given format details in -
  http://hincklab.uthscsa.edu/html/soft_packs/msi_docs/insight980/formats980/ClassicFiles.html.

  The previous code didn't recognize such a spacegroup as it strictly
  looked for 8 fields after tokenizing them using default delimiters as
  space, tab, newline.

- It is legal to have .car files with PBC=ON and no space group defined
  in the fifth line and just have PBC and a,b,c,alpha,beta,gamma
  parameters. Such structure is considered to have lowest symmetry
  space-group as P1. This means there are no symmetry operations in play
  and all atoms are explicit within the unit cell. The .car files for
  H2O and polymers fall under this category since they are amorphous but
  are periodic.

- Added tests to ensure this is working.
Merge pull request #26 from schrodinger/master

Improve space group support in .car files
Merge pull request #18 from mcs07/mdlextension

MDL extension for zero-order bonds
OBGUI.cpp: Fix compile

Complained about ambiguous conversion from const char* to const
wxString.  Used UTF8 encoding as in example in wxWidgets wiki since that
covers also the ASCII case.
Merge pull request #27 from Reinis/fix_gui_compile

OBGUI.cpp: Fix compile