cosmetic changes

* ajax loader (not presented)
* cosh fields that are not correct get a red error colouring (text and
border) to help show it's not a number that's been input
adding in partial caching and...

slowly improving code to remove global variables
sharing urls

ref #6
help positioning and pretty replace

ref #15 (pretty replace)
#14 (help toggles -- NOT complete)
prettying up the elements.

a proper colour palette is needed though.

elements for the help are modified to be less code
improving the colour palette

I am not a designer, but it's certainly more clean

Palette url: http://paletton.com/#uid=33L0u0kdou14vOM8GCPiwoTnBjH

ref #16
Merge pull request #17 from sgazard/experimental

Experimental