Correct Broken Link in README.md

Correct the link to the PropER chapter by adding the missing underscore.
Merge pull request #5 from stevenproctor/master

Remove extra hyphen throwing off formatting -- thanks
Merge pull request #4 from jrgarcia/patch-1

Correct Broken Link in README.md
More on dialyzer
Merge branch 'master' of github.com:zkessin/testing-erlang-book
Where to place tests #7
Working on the outline, more on dialyzer
Improving the readme about tools
Fixing typos, removing unnecessary empty lines and expanding some shortcuts/acronyms.
Merge pull request #10 from afronski/master

Fixing typos and Removing empty lines
Fixes typo (weekly => weakly)
Merge pull request #11 from ZeissS/patch-1

Fixes typo (weekly => weakly)
Start section on PropER
More on dialyzer
Merge
starting on tagged types
add best practices chapter
more on eunit
move some text to the best practices chapter
a bit of tweeking