Made the code strictly C89 compliant

Now, we are able to compile on Visual Studio 11. Ofcourse, we get
warnings about "insecure" localtime and asctime, but that's to be solved
later on.
Changed the rounding to "DOWN"

Based on Ameir comment, I changed the rounding to "DOWN" and added a
TODO item to check what Fiqh says. I alo updated the CMake file with
Windows compile options. I got this code compiled under Visual Studio
11, however, it generates tons of warnings related to insecure C
functions like: localtime, asctime, strtok, etc. These are unfortuantely
the only portable ones.
Change threshold to 4 minutes in run_tests

I changed the altitude in the configuration of Mecca and Eindhoven.
The altitude of Mecca is set now to the altitude in Al-Masjid Al-Haram
(~ 300 m) and for Eindhoven it is around 21 m. We need to see the reason
for the increased difference between the Official Umm Alqura values and
the computed values. I suspect that for Um Alqura, they use and altitude
equal to the sea level.
Fixed warnings from MSVC/Intel/Clang compilers

It is interesting to see how much more warnings one can get when he uses
a compiler other than gcc :-D
Reorder struct members to avoid padding

Compilers add padding bytes automatically. Now, we re-order struct
members in such a way that we avoid automatic insertion of padding
bytes.
Fixed Isha bug reported by Ameir

Now, we use the proper parameters
Fixed the rounding bug reported by Ameir

Now, we round always to nearest
Update README.md

Added informaiton about the test suite
Merge pull request #28 from mohamed/master

Strict C89 compliance and fixing the rounding