sword 1.7.3 (new formula)

Sword is a mature programming library for working with biblical and related
tests that is used by different bible readers such as Xiphos and BibleTime.
This commit adds a first version of a formula for sword to homebrew.
Make add:
```ruby
option "with-icu4c", "Uses icu4c for unicode support"
option "with-clucene", "Uses clucene for text searching capabilities"
```
?