Update link to Mark Leisher's tools and fonts

* Update link to ClearlyU font collection
* Update link to gbdfed Bitmap Font Editor
* Remove link to xmbdfed
Merge pull request #543 from JoesCat/master

gutils/gimagewritexpm.c, write mono bitmaps too.
Merge pull request #544 from JoesCat/master

added grey to gimagewritexpm.c
Merge pull request #541 from behnam/develop

Update link to Mark Leisher's tools and fonts