Get rid of TSRMLS for phalcon_base64_XXX() and phalcon_md5()

665b680880d6a4f8cc561ba82d8082938716ab9c introduce `phalcon_base64_encode()` and `phalcon_base64_decode()` which were declared with `TSRMLC_DC`.

However, the rest of the code did not pass `TSRMLS_CC` to them which resulted in errors:

```
/home/travis/build/phalcon/cphalcon/ext/crypt.c: In function ‘zim_Phalcon_Crypt_encryptBase64’:

/home/travis/build/phalcon/cphalcon/ext/crypt.c:352:2: error: too few arguments to function ‘phalcon_base64_encode’

/home/travis/build/phalcon/cphalcon/ext/kernel/string.h:76:13: note: declared here

/home/travis/build/phalcon/cphalcon/ext/crypt.c: In function ‘zim_Phalcon_Crypt_decryptBase64’:

/home/travis/build/phalcon/cphalcon/ext/crypt.c:376:2: error: too few arguments to function phalcon_base64_decode’

/home/travis/build/phalcon/cphalcon/ext/kernel/string.h:77:13: note: declared here
```