Improved & generalized camelcase linter [patch]

[fangly]

Hi Jim,

I have improved the camel_case_linter() function by:
1 / adding extra tests
2/ making sure that names that don't use a clear convention are not reported as camelcase, e.g. "my_confusedExample" is not camel case.
3/ adding support for digits in names, e.g. "html5Converter" would be camel case
4/ handling private objects adequately, e.g. ".myFunction" is camel case
5/ adding an option to lint UpperCamelCase, lowerCamelCase, or both

Here is a patch, which you will hopefully be able to include in lintr:
0001-Improved-generalized-camel-case-linter.zip

Cheers,

Florent

[fangly]

Superseded by #194