ibrcommon: ibrcommon.h added to reflect the library features

Using this header an application can check if specific features of the
library are included in the build configuration.
ibrcommon: Fix buffer size of HMacStream

The buffer sizes for processing buffer and hash buffer were reversed.
ibrcommon: Add hash stream for MD5
ibrdtn: Use MD5Stream class to convert application strings into numbers
tools: Remove dependency on openssl
ibrdtn: Automatically detect support for the bundle security protocol
daemon: Automatically detect support for BSP and 6LowPAN