[PATCH] Implement support to get data from import/export tables

[Jakub Zawadzki <darkjames at darkjames dot ath dot cx>]

So, here are two patches.

importexports.diff introduce new structs, and new JUMP_TABLE: 
BFD_JUMP_TABLE_IMPORT

importexports-pe.diff introduce support to get import/export table in COFF/PE files.

Later I'll try to rewrite _bfd_XX_print_imports() and _bfd_XX_print_exports()
to use bfd_get_libraries() bfd_get_exports() instead of duplicating code.

However I cannot guarantee that output of _bfd_XX_print_imports() will
be the same as after bfd pe_print_idata()
[So should I do it?
Or we can have duplicated code of reading import && export tables to avoid regressions?]

I tried my best to fit into bfd coding style.
However mine is quite different, so if I made mistakes than sorry.

Tested with --enable-targets=all

Attachment: importexports-pe.diff
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Attachment: importexports.diff
Description: Text document