SFTP: Add support for files larger than 2GB

0x7FFFFFFF is about 2GB. To support larger files floating point is used
SFTP: typo
typofixes
optimizations
SSH2: window size is server -> client, not client -> server
Merge remote-tracking branch 'origin/largerfiles'
Merge pull request #106 from petrich/optimizations

Optimizations
ASN1: CS adjustments
SFTP: $content isn't defined when file is being written to
Merge remote-tracking branch 'vlajos/master'
Merge branch 'master' of https://github.com/phpseclib/phpseclib
SSH2: return false (without error) on channel failure

Also update error message. SFTP, for example, makes a channel request even though it's not asking to open a pseudo-terminal.
SFTP: attempt to utilize SFTP via CLI if subsystem is unavailable
Merge branch 'master' of https://github.com/phpseclib/phpseclib
SSH2: fix broken grammer from next to last commit

Thanks, bantu!
SFTP: add the same multi-factor auth support that Net_SSH2 enjoys
Twofish: bugfix in setPasswort()

fixed bug in setPasswort()... (occurred only in Twofish.php)
Merge pull request #14 from phpseclib/master

sync