Add additional tests that initial "xr" is treated as a vowel sound as is initial "y\<consonant\>".  tests were also added to assure that adding handling of these special cases does not break appropriate handling of other initial "x" and initial "y" cases.

An example exercise solution that passes these new tests is substituted for the original example code.
Add more stub files for elixir exercises
Merge pull request #1054 from dpneumo/Additional-PigLatin-tests

Add additional tests to pig-latin that initial "xr" is treated as a vowel sound as is...
Merge pull request #1055 from petehuang/add-stub-files

Add more stub files for elixir exercises
Merge pull request #1057 from zilkey/master

Atbash completion and beer-song conversion to Go
teams: Add name field to teams

Create a new migration that copies the slug into the team name
by default, and update the model object to use the slug as default
for new teams.
test/exercism/team_test: Extract common users

Move alice and bob to setup method.
Merge pull request #1058 from sit/add-team-names

Add team names
Add difference of sums exercise for elixir
Merge pull request #1056 from petehuang/master

Add difference of squares exercise for elixir
implement binary search tree in Go