added the option not applicable to visual tests and selected reading tests

Removed the following two tests from Visual Tests. These will be put in advanced test book.

[FUNDAMENTAL] visual-310
Change highlight text color.
 [FUNDAMENTAL] visual-410
Change highlight text background color

Modified the following reading test. Now read by paragraph and page will be an advanced test.
FUNDAMENTAL]  nav-710
Read by character, word and line.  Check if it is possible to read the paragraph given below by character, words and lines.
For sample text I have used text and images available on IDPF website. Hope there are no copyright issues.
Made changes in the Front matter