Performance: replace several jqmData() function calls with getAttribute() to improve performance. It is the same as #5466.

Hi, All.

I saw that #5466 PR was closed by @gabrielschulhof a few days ago.
There are many lines using jqmData() and my team checked them what lines could be changed with get/setAttribute.

And some lines using jqmData() return true or false value so my team thought that it would be better to make a new function including get/setAttribute to handle that case.
@gabrielschulhof, you made getAttrFixed() on buttonMarkup.js, so what do you think that we will define getAttrFixed() in global area and use it in other places?

* Tests : The code has been tested on several jQM widgets using qunit.js.
* Modified code is followed the jQuery Core Style guide.
* Scope : Performance improvement.

If there are any problems or mistakes on that PR, please let me know. Thanks in advance.