Input types should be matched in a case insensitive way

[stof]

This involves 2 tasks:

• updated the NamedSelector to match the type attribute in an ASCII-case-insensitive way to respect the HTML spec
• adding tests using non-lowercase values in the type attribute to the driver testsuite to ensure that all drivers are treating such values properly.

See #572 for the previous discussion about it

[aik099]

Here is how it's possible to make case-insensitive comparison:

• http://stackoverflow.com/questions/1625446/problem-with-upper-case-and-lower-case-xpath-functions-in-selenium-ide/1625859#1625859
• http://stackoverflow.com/questions/2893551/case-insensitive-matching-in-xpath

[aik099]

PR created, ready for review.

[stof]

Reopening as the PR was doing only the first part, not the second one

[aik099]

@stof , the PR for 2nd part of this task needs to be created and then all will be ready (except for changelog update) for the 1.6 release.

[aik099]

@stof , is milestone 1.6 right for this issue? I propose to move it to 1.6.1 or 1.7.0 milestone and close the 1.6 milestone because version itself was already released.

[stof]

Given that we released 1.6 without the second part, we should indeed put it in a different milestone