provide follow features implementation:

1) Support of CAT-B RU (i.e. precoding in RU)
2) Add support for alpha and beta value when calculating SFN based on GPS time
2) Add unit test framework
3) More bugs fixes
Additional Information available in the readme.txt file
xran root refers to the o-du/phy/fhi_lib folder
 
Issue-Id: ODULOW-8 ODULOW-9 ODULOW-10

Change-Id: I9f39128214318a426503509bd4e376e0befd5e7f
Signed-off-by: Zhimin <zhimin.yuan@intel.com>