[Freeciv-Dev] errors in in-game documentation (PR#758)

[jdorje@xxxxxxxxxxxxxxxxxxxxx]

Full_Name: Jason Short
Version: CVS
Distribution: Built from source
Client: Both (or N/A)
OS: Red Hat 7.1/i686
Submission from: (NULL) (151.201.20.68)


I was looking through the in-game documentation (English), and some of it 
seemed to have obvious grammatical mistakes or inconsistencies.

I edited data/helpdata.txt to make some slight fixes here.  It a very 
small improvement, but certainly an improvement.

The patch is at: http://devon.dhs.org/freeciv/documentation-fix.patch.

Fixes include:
- Making the tense consistent in the topics of the "playing" help.
- Making the spelling of defense consistent.
- Changing a nonsensical sentence to a better one.