* Added SFTP file transfer resume support on both PUT and GET. Internally SFTPFileTransfer has a few sanity checks to fall back to full replacement even if the resume flag is set. 

SCP file transfers have not been changed to support this at this time.

* Added JUnit tests for issue-700

* Throw SCPException when attempting to resume SCP transfers.

* Licensing

* Small bug resuming a completed file was restarting since the bytes were equal.

* Enhanced test cases to validate the expected bytes transferred for each scenario are the actual bytes transferred.

* Removed author info which was pre-filled from company IDE template

* Added "fall through" comment for switch

* Changed the API for requesting a resume from a boolean flag with some internal decisions to be a user-specified long byte offset. This is cleaner but puts the onus on the caller to know exactly what they're asking for in their circumstance, which is ultimately better for a library like sshj.

* Reverted some now-unnecessary changes to SFTPFileTransfer.Uploader.prepareFile()

* Fix gradle exclude path for test files

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

- Set KeepAlive interval before connecting

* Replaced PKCS5 parsing with PKCS8

- Moved tests for PEM-encoded PKCS1 files to PKCS8
- Removed PKCS5 Key File implementation

* Added PKCS8 test to retry password after initial failure

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

Co-authored-by: Alex Heneveld <alex@cloudsoft.io>

#743)

Previously, AuthGssApiWithMic used params.getUsername() to create the
local client credential object. However, at least when using the native
GSS libraries (sun.security.jgss.native=true), the username would need 
to be something like "user@EXAMPLE.COM", not "user", or the library is 
unable to find credentials. Also, your remote username might not be your
local username.

Instead, and more simply, call the GSSManager#createCredential variant
that just uses default credentials, which should handle both of these 
cases.

Tested on Windows using SSPI. I haven't tested this patch on Linux but I
have confirmed that this form of call to createCredential works as I 
expect when using the native GSS/Kerberos library there too.

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

)

* Added Transport.isKeyExchangeRequired() to avoid unnecessary KEXINIT

- Updated SSHClient.onConnect() to check isKeyExchangeRequired() before calling doKex()
- Added started timestamp in ThreadNameProvider for improved tracking

* Moved KeepAliveThread State check after authentication to avoid test timing issues

#813)

* Fix #805: Prevent CHANNEL_CLOSE to be sent between Channel.isOpen and a Transport.write call

Otherwise, a disconnect with a "packet referred to nonexistent channel" message can occur.

This particularly happens when the transport.Reader thread passes an eof from the server to the ChannelInputStream, the reading library-user thread returns, and closes the channel at the same time as the transport.Reader thread receives the subsequent CHANNEL_CLOSE from the server.

* Add integration test for #805

* Support SSHClient.authPassword on FreeBSD

FreeBSD "keyboard-interactive" prompt is "Password for user@host:"

* Add test for PasswordResponseProvider