#156 EGifSpew leaks SavedImages (and more).

[Ono-Sendai]

EGifSpew writes out SavedImages, but it does not free them -
There is no call to GifFreeSavedImages() in EGifSpew.

This results in a memory leak when using EGifSpew.

[Ono-Sendai]

It also doesn't free the main extensions - there is no call to GifFreeExtensions().

[Eric S. Raymond]

This is intended. The design assumed you might want to write once, modify the in-core data, and write again