Remove extra whitespace
NMatrix::BLAS.cblas_scal make use of CBLAS

First of all, `xscal` (x in {s,d,c,z}) seems to be a BLAS level 1
function instead of a LAPACK one according to the standard[1]. Thus I
reworded it to reflect reality and added calls to the cblas routines
(which also solves an old FIXME).

I still don't know how everything works in the NMatrix C/C++ world, but
it appears to work correctly.

[1]: http://www.compsci.wm.edu/sciclone/documentation/software/math/ATLAS/blas-report.pdf
Add specs to NMatrix::BLAS.cblas_scal
Fix indentation
Add documentation for NMatrix::BLAS.cblas_scal
[BLAS scal] Fix compilation problem

I introduced a small problem by *not reading* variable names and blindly
copying BLAS interfaces. Anyway, this patch should make compilation
(and, obviously, specs) work correctly.
Merge pull request #230 from agarie/blas_scal

Make NMatrix::BLAS.cblas_scal call BLAS functions
Remove some compiler warnings

I mostly added some type casts for unsigned integers and such.
Updated README

I forgot to add the IxAMAX BLAS function to the README and there was an
outdated comment regarding documentation.

This commit also removes a lot of extra whitespaces in `ext/nmatrix/`
files.
Removed curly braces in if statement

As per John's request.