- Remove StringEx.CS
- Update all dependencies
- Eliminate all warnings

Note: If you want to compile it by yourself, please make sure
do NOT use `no-asm` configure option, since the main point of
this commit is to utilize assembly in openssl

Add OpenSSL test

which is hardware accelerated compared to AES-GCM in mbedtls

We have to drop this commit when mbedtls support hw-accelerated GCM
when compiling with MSVC

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- drop unused using directive
- add a comment

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

* Refine encryption

- Add AES-CTR, blowfish and camellia ciphers

aes-256-ctr
aes-192-ctr
aes-128-ctr
bf-cfb
camellia-128-cfb
camellia-192-cfb
camellia-256-cfb

- Merge the previous PolarSSL and MbedTLS
- Switch to MbedTLS's cipher layer functions
- Add workaround to set cipher operation(encrypt/decrypt)

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

* Add function to get MbedTLS cipher context size

and drop hard-coded ctx sizes

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>