Direct Solve: Moved details to detail-namespace, polished public interface.

No more collisions with GMRES anymore. Resolves #61
Add travis and coveralls support.
CUDA: Added libstdc++ on MacOS Mavericks and above.

Discusssion here:
https://github.com/viennacl/viennacl-dev/issues/106
Vector: Added min() and max() routines.
GEMM on CPU: Fixed race condition with OpenMP.
sliced_ell_matrix: Fixed OpenMP race condition and use unsigned type for OpenMP loops.
Device-DB: Using scalar types for vector operations.

Vector types lead to compilation issues on NVIDIA GPUs with abs(), since
 x = abs(y)
does not compile due to incompatible vector types.
CUDA: Fixed bug in as() kernel for scalars.
CUDA: Fixed missing else-clause when wrapping a CUDA buffer.

Might have gotten lost during refactoring?
CUDA: Added CTOR for matrix to wrap user-provided buffer.

Also includes a new example showing the use case.
Resolves #69.

Reported-by: Pushkar Ratnalikar via viennacl-devel
Fix OpenCL kernel cache so as not to use same binaries across different contexts
sliced_ell_matrix: Fixed conversion warning in matrix-vector product.
Device-DB: Added NVIDIA GTX 750 Ti.
Device-DB: Added NVIDIA GeForce GTX 470.
GMRES: Added pipelined implementations for all three backends.

Only requires four kernels per iteration, which is much better than
the Householder version. Implementation follows Algorithm 2.1 in
Walker, Zhou: "A Simpler GMRES" (1994)
GCC 4.6: Fixed all warnings with -Wall -pedantic -Wextra -Wconversion -g
Clang 3.0: Fixed a bunch of warnings at high warning levels.

Flags used: -Wall -Wextra -Weverything -pedantic -Werror
-Wno-exit-time-destructors -Wno-global-constructors -Wno-padded -Wno-weak-vtables
Device-DB: Added NVIDIA Tesla C2050.
Device-DB: Added AMD Cedar architecture.

Obtained on a Radeon HD 5450. Very low-end GPU, profile aims at compatibility
rather than performance.
Device-DB: Added AMD Barts architecture.

Derived from a Radeon HD 6850 with a tuning run.