CHANGES: Set log level using environment variables

Removed hard-coded log levels.
The following environment variable are introduced for more control over log level:

ENABLE_DEBUG_DIS64
ENABLE_DEBUG_INPUT_BFD
ENABLE_DEBUG_INPUT_DIS
ENABLE_DEBUG_EXE
ENABLE_DEBUG_ANALYSE
ENABLE_DEBUG_ANALYSE_PATHS
ENABLE_DEBUG_ANALYSE_PHI
ENABLE_DEBUG_OUTPUT

Removed 2 extra logs not needed anymore from test_case.cpp.

Signed-off-by: Arun Prakash Jana <engineerarun@gmail.com>