Change version number to 1.0.15

VERSION

doc/copyright.rst

ltfatpy/__init__.py

ltfatpy/comp/arg_firwin.py

ltfatpy/comp/assert_groworder.py

ltfatpy/comp/assert_sigreshape_post.py

ltfatpy/comp/assert_sigreshape_pre.py

ltfatpy/comp/comp_dct.pyx

ltfatpy/comp/comp_dst.pyx

ltfatpy/comp/comp_gabdual_long.pyx

ltfatpy/comp/comp_gabtight_long.pyx

ltfatpy/comp/comp_hermite.py

ltfatpy/comp/comp_hermite_all.py

ltfatpy/comp/comp_isepdgt.pyx

ltfatpy/comp/comp_isepdgtreal.pyx

ltfatpy/comp/comp_pgauss.pyx

ltfatpy/comp/comp_sepdgt.pyx

ltfatpy/comp/comp_sepdgtreal.pyx

ltfatpy/comp/comp_sigreshape_post.py

ltfatpy/comp/comp_sigreshape_pre.py