many_errors
temporary
add test for Chart#size
test for Chart#size pass.
add other test for 0.61
0.61 all test pass
disable regression/test_vml04.rb because it takes much time for testing.
add examples/hide_row_col.rb
add v0.61.0 comments.
Merge branch '0.61' of github.com:cxn03651/write_xlsx into 0.61

Conflicts:
	lib/write_xlsx/chart.rb
	lib/write_xlsx/worksheet.rb
remove Worksheet#set_vml_data_id because nobody call this.
remove some tests because some method has been removed.
add Button class
set version to v0.61.0