Merged branch 'rails4' into 'master'
Got rid of old rails 3.x and ruby 1.8 things.
Merge branch 'merge_rails4'
exists? handle numeric strings like stock rails

Should solve #414
More clear explanation of difference between version 4 & 5 in README.md
fixed typos
Merge pull request #421 from hajder/master

More clear explanation of difference between version 4 & 5 in README.md
Don't make class explicitly abstract to allow test to run
Fix the :scoped module
Fix STI support
Fix SimpleI18n module
Documented change to slug generation behavior
Merge pull request #415 from jheiss/exists-numeric-string

exists? handle numeric strings like stock rails
Add license to gemspec

[ci skip]
Tweak version name

[ci skip]
Update benchmark script to for FriendlyId 5
Force join to improve performance of external slugs

Before:

    Using ruby 2.0.0 AR 4.0.0 with sqlite3 (in-memory)

                                      user     system      total        real
    find (external slug)          4.870000   0.050000   4.920000 (  4.930922)
    insert (external slug)       14.810000   0.050000  14.860000 ( 16.201902)

After:

    find (external slug)          1.580000   0.030000   1.610000 (  1.619796)
    insert (external slug)        8.020000   0.030000   8.050000 (  8.087657)
Add some spaces
Clean up scope/finder setup
Simplify logic in #exists?