New structure "cmyth_epginfo" replacing "cmyth_program"

Hi Christian,

Here you will find my improvement about EPG. Now old structure cmyth_program is replaced by cmyth_epginfo. Memory segments are allocated and freed using librefmem. The new class MythEPGInfo is the smart pointer and memory is automatically freed now. Also string type attributes have no fixed size like before and full description of program is available.

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