static link TA-LIB on Linux

[elsejj]

Static linking TA-LIB makes ta-lib-python a self-contained package that does not require TA-LIB to be installed on the target system. This makes it easier to deploy ta-lib-python.

This patch adds several Makefile targets.

• The new talib_static target downloads and compiles a static version of TA-LIB to the current directory, for use by other build targets.
• Targets with the suffix _static added to existing build targets link to the static version of TA-LIB.

To support building ta-lib-python with a static version of TA-LIB, the setup.py script has been updated to add a new variable named lib_talib_static_lib. This variable is set to the file name of the static library if the environment variable TA_LINK_STATIC is enabled. The corresponding settings are then made during build_extensions to link the static library.