libb64: Base64 Encoding/Decoding Routines

Changelog

Version 2.0.0 Release

Introduce version macros for detection of incompatible API / version
size_t as argument to allow longer base64 encoded strings
re-introduce line break functionality this time with line with configurable
add flags field for encoder to mage it configureable (currently unused)
add functions to calculate required output buffer maximum lengths
change in-/out-pointers to void* as we don't need to make assumptions about kind of data

Version 1.4.1 Release

Fix differing prototypes in cencode.h and cdecode.h
Fix compiler errors due to C++ style "//" comments and -pedantic option on gcc

Version 1.4.0 Release

add ARM compatibility by Harry Rostovtsev
Fix integer overflows in decoder by Jakub Wilk
Make Visual studio project compile again, use Visual Studio 2013
switch to warning level 4 and get rid of warnings
init encoderstate on instantiation to make encode() work out of the box
Make project compile with x64 compiler

Version 1.3.0 Release

Remove newlines in output because json doesn't allow them in string values.

Version 1.2.1 Release

Fixed a long-standing bug in src/cdecode.c where value_in was not correctly checked against the bounds [0..decoding_size) Thanks to both Mario Rugiero and Shlok Datye for pointing this out.
Added some simple example code to answer some of the most common misconceptions people have about the library usage.

Version 1.2 Release

Removed the b64dec, b64enc, encoder and decoder programs in favour of a better example, called base64, which encodes and decodes depending on its arguments.
Created a solution for Microsoft Visual Studio C++ Express 2010 edition, which simply builds the base64 example as a console application.

Version 1.1 Release

Modified encode.h to (correctly) read from the iostream argument, instead of std::cin. Thanks to Peter K. Lee for the heads-up.
No API changes.

Version 1.0 Release

The current content is the changeset.