Updated extpy makefile to replace tar by gtar

Additionally modified the PyXML build parameters to look for expat at $ACSROOT/lib
Reordered linker arguments to make it work properly
Changed permissions of vlt makefiles to add a+x
Replaced gtar by tar
Added missing libraries for the linking of logging binaries
Added -Wl,--no-as-needed option to allow log4cpp to link against dl
Added missing libraries for linking maci binaries
Added extra libraries to link task binaries
Replaced python2.6 by python2.7 as the library to link in acstime