Support parsing of datauri's without mediatype

Merge pull request #14 from jczerwinski/allow-blank-mime

Support parsing of datauri's without mediatype.
Also tag as 0.2.5

0.2.4: enforce png for tests

Luckily via.placeholder.com returns png even if doc says default is gif.
Anyway it also returns png even if you explicitly ask for a gif...

0.2.3

Fix sami version
Add support for SVG formats

0.2.2

Update package to run tests with more PHP versions

0.2.1

Adds composer compatibility with Symfony 3

0.2.0

Adds a new method to build a data URI from a remote file using CURL.

This release adds an optional dependency on ext-curl to use that new feature.

0.1.1

• Fix parsing of mime types that contains plus signs and dots (#4)