refactor hash parsing, fixes issue with autoplaying media not starting from internal links on mobile devices

fix for windows
line ending difference caused failure
now simple.md content mirror deck1

Fix copy/paste-o

Update comments about markdown slide separators

They might have been correct once upon a time, but apparently not since "---" became the default.

new shortcuts; alt+arrow key skips fragments, shift+arrow key jumps to last slide in the given direction #1105

fix(highlight): allow pre fragments