add missing border styles

hi
in reference guide - Available border styles:
* none 
* dashDot
* dashDotDot
* dashed
* dotted
* double
* hair
* medium
* mediumDashDot
* mediumDashDotDot
* mediumDashed
* slantDashDot
* thick
* thin

in HtmlReader borderStyle func:
* thin
* dashed
* dotted
* medium
* thick