basic app skeletons for wxMac
Merge commit 'e65fde3'
from master branch of original repo

Conflicts:
	.gitignore
add WebView to the main frame
add Quit menu
structurally support multiple frames
merge two headers into one
move close_child to delete_child
rename App
properly handle global menu bar
remove unrelated comment
ignore .DS_Store
open file menu
add sundown library
Markdown Renderer
make renderer return wxString
remove every compiler warnings
did not free renderer memory
open all links out of the page