update Content#parse for roots v3
update Content#save for roots v3
correctly handle files with no markdown content below

also:
- don't break on .md files
- clean up code for Content class
don't compile client during travis tests

- travis build breaks when compiling because of a file system permission/access issue
shorten auth config syntax, closes #30
use consolidated uploader config syntax, closes #29
move upload directory under uploader config key
update tests with new config syntax
update readme with config syntax
escape markdown content