test for bug fix escaping of special character in URLs to Worksheet#write_url.
bug fix : escaping of special character in URLs to Worksheet#write_url.
add test for 0.60 (Added Excel form buttons via the worksheet insert_button() method.)
0.60 all tests pass
bug Fix for 0 access/modification date on vbaProject.bin files extracted using extract_vba.rb.
add v0.60.0 comments
set version to v0.60.0
Merge branch '0.60'