Changes between releases 3.40 and 3.50

* correction of a bug in anafast when maskfile or theta_cut_deg are used in combination with iter_order>0,
* addition of zbounds in alm2map, alm2map_der, alm2map_spin, in order to simulate (faster) a signal on only a fraction of the sphere,
* improved support for version 18 and more of Intel C and F90 compilers in configure script,
* edition to fitstools.F90 allowing a proper compilation with g95.

Version 3.50, 2018-12-10