Handle 'space' character correctly in MacRomanEncoding (bug 878026)
Treat fonts with the same font descriptor, encoding and unicode map as aliases

Different fonts can point to the same font descriptor
(see https://github.com/mozilla/pdf.js/issues/4339 for details). With this
commit such fonts are treated as aliases if they have also the same encoding
and the same toUnicode map. The according info is stored on the font descriptor.
This change must also ensure that aliases use always the same font name
because translated fonts can get cleared depending on the CLEANUP_TIMEOUT setting.
Workaround for cases where FontName in the FontDescriptor differs from BaseFont in the Font (bug 847420)
Merge pull request #4578 from Snuffleupagus/bug-847420

Workaround for cases where FontName in the FontDescriptor differs from BaseFont in the Font (bug 847420)
Merge pull request #4569 from Snuffleupagus/bug-878026

Handle 'space' character correctly in MacRomanEncoding (bug 878026)
Merge pull request #4423 from chriskr/font-aliases

Treat fonts with the same font descriptor and encoding as aliases