Forms: Make [readonly] inputs easily readable
Differentiate [readonly] form inputs from [disabled]

This commit builds on top of jaseg's commit (4c5caee).
Readonly form inputs have a different style from both
[disabled] and normal inputs.

[readonly] inputs do not have the default :focus style.
update HISTORY.md with [readonly] input enhancement
remove cursor property for readonly inputs
add issue + committer reference
indent
modify colors to be consistent with other colors in Pure
Merge pull request #132 from tilomitra/readonly-input

Differentiate [readonly] inputs from [disabled] inputs