Fix bug where sampleBufferResize did not assign result
Use CharString functions instead of raw C-API
More error logging in WAVE file finalization

Fixes #150.
Log build type when configuring
Small performance optimizations writing PCM data

Running MrsWatson through callgrind shows this area as being the biggest
(fixable) bottleneck, these changes improve the application's performance,
albeit very slightly. However this refactoring is very safe so it's a sure
bet.
Internal plugins must declare I/O counts