bugfix and optimization only for release-builds

[RobertHue]

Hey

I found some bug under a certain condition. When you want to build for only static libraries the compiler says that it cannot find the target noise (which is the .dll or .so). fix:

• the target and further cmake commands for it are put together now only for shared builds (BUILD_SHARED_LIBS==TRUE)

Another little bug which just occured to me under windows with MSVC compiler. That is when you are in debug build and are using the compile flag /Ox (-O3). This combination is not possible and the compiler sees that as an error: fix:

• the optimization -O3 wasn't removed. it's just only enabled on RELEASE-builds. Which is also described inside the README now.

Also the following:

• Little refactorings like common lowercase ensured
• Wall is disabled by default. Unless you are working inside of libnoise, to fix some bugs, you should enable that. I wouldn't like it myself when some library verbositly throws warnings like "size_t not compatible with int" at me. Without me being able to fix those without touching the library.

I hope those changes are fine for you.

[RobertHue]

I also hope it works to build under linux (dynamic and static) for you. As I don't have a compiler for that.