New features in chemtool 1.6

- universal import mode based on BABEL (both openbabel and babel supported)
- Formula weight calculator now handles all main group elements and the first
  row of transition elements, and accepts greek phi as phenyl substituent.
- Movable hexagonal or square grid backdrop
- Improved SVG export, optional preview bitmaps in EPS export, optional EMF
  export
- Cursor key support for pixel-precise drawing and moving 
- The cleanup function now corrects bonds that deviate from ideal
  horizontal or vertical orientation by a single pixel
- Color support (bonds and text can be red,green,blue,cyan,magenta or yellow). 
- Default bond length now configurable, additional grid positions at two and 
  three times this length added
- Added a brief help text to accompany the 'About' window in the 'Help' menu.
- Added alternate text font (Times Roman)
- An attachment site can be marked before saving a molecule or fragment,  
  which act as reference point for adding this fragment to other molecules 
  (previously, this had to be the first atom in a file). Attachment sites are 
  marked in the preview window by a small x.
- Background color can now be chosen for screen display and EPS export, and
  drawing whiteout boxes under labels is now an option ( off by default !). 
- Text at 8,10,12,14,17,20 and 24pt can now coexist in a drawing. 
- Increased allowed label length to 100.
- Improved rendering of dashed wedge and dotted lines
- Improved text kerning in xfig-based print and export.
- It is now possible to place an auto-incrementing counter at the cursor 
  position for numbering sites.
- Changed double bond drawing code to no longer switch sides depending
  on drawing (or rotation) angle. (As a result of this, some older drawings 
  will need fixing)
- Rescaling a molecule now also scales its labels. Downscaling beyond 
  zero size (causing strange inversions) is no longer possible. 
- Renamed the "Orbitals" template menu to "Symbols" and added "plus", 
  "minus" and a rearrangement arrow to it. 
- Added two new bond types, a triple bond with all three lines equal,
  and a quadruple bond. 

