Remove redundant default (Int)
Do not filter primes and backticks in test for totality
Move tests for emphasised text under parseString

(it's a string level markup construct after all)
Add more specs for emphasized text
Make parseString total

(the major catch here was that it still failed for the empty string)
Failing spec for Unicode escapes
Fix Unicode escaping issue
Rename skipChar to skipSpecialChar

(+ make sure that it only skips special characters)
Use mfilter instead of guard