upload exttab2 code to gitHub for better accessibility

Original source code by disorder Chang, last modified by Ashish Myles
(version 0.3.0 2010-08-28)
exttab3-rc2 upload
toolbar icon to insert frequentry used table pattern
caption bug fix
add style.css
Merge pull request #1 from ssahara/exttab3

merge exttab3 branch to master