INT-3162 Fix AbstractScriptExecutor Thread-Safety

JIRA: https://jira.springsource.org/browse/INT-3162
INT-3091 Fix Concurrent (S)FTP Transfers

byte[] and String payloads were written to a temporary file.

If the same message is transferred to two different destinations
concurrently, one of the adapters could remove the temporary
file while the other was using it.

Don't use a temporary file for these payloads, simply use the
payload byte[] [or a String.getBytes()] as the InputStream
passed to the Session.write() method.

Polishing

Polishing - Add WARN For Missing File

+ Test

JIRA: https://jira.springsource.org/browse/INT-3091
INT-3074: JDBC: Make generateSql as UP-TO-DATE

* remove `overwrite: 'true'` from `generateSql` task
* add `cleanSql` task

JIRA: https://jira.springsource.org/browse/INT-3074
INT-3170 Update Project Repo in Root Files

s/SpringSource/spring-projects/
INT-3171: Polishing Aggregator tests

* Increase waiting timeouts
* Get rid of `Thread.sleep` when it's dangerous

JIRA: https://jira.springsource.org/browse/INT-3171
INT-2866: Add (S)FTP `local-directory-expression`

* Add `local-directory-expression` to (S)FTP Outbound Gateways
* Add `FtpServerRule` to Apache Mina embedded FtpServer
* Add tests for (M)GET and `local-directory-expression`:
FTP tests uses `FtpServerRule`, SFTP tests need testing on real SFTP server

JIRA: https://jira.springsource.org/browse/INT-2866

INT-2866: Documentation

INT-2866 Polishing

- Remove leading /
- Change \ to / in invalid test
- Clean up after sftp

Tested with real SSH.

INT-2866 Polishing - Add Mock SFTP Test

Run with -Dspring-profiles-active=realSSH to run with a real SSH server.

Assumes ftptest/ftptest account on localhost with the following directory tree in the user's root...

  $ tree sftpSource/
  sftpSource/
  ├── sftpSource1.txt
  ├── sftpSource2.txt
  └── subSftpSource
      └── subSftpSource1.txt

INT-2866: Polishing

INT-2866: change `remotePath` to `remoteDirectory`

Doc Polishing.