move ScRefreshTimerProtector into its own header file

So that, we don't have to include "refreshtimer.hxx" in docsh.hxx.
Also implement destructor in source file.

Change-Id: Ie0251ad3511b44cf1dd6dae34e22ade0ab32cec4
ScRefreshTimer: implement methods in source file

And don't export any of them.

Change-Id: Ib29eec6765f0fe71c9c7fbc82b0531f562b6404a
ScRefreshTimer: allow to run in another thread

Change-Id: Ie817f55ebeadda78225aafd9a2014d2d2c206a00
add menu item for data streams dialog

Change-Id: I2f27afbaf91b31be2711fcb581bfd86bc103f1cb
implement very simple SvScriptStream to read from process

It inherits from SvStream, so it could be used easily.
Basically, it's just a simple wrapper around
osl_executeProcess_WithRedirectedIO() and osl_readFile().

Change-Id: Ifa225c87d2c9be7e71ea113b0832a4fe83ec65b3
add data streams dialog .ui file

Change-Id: I184f824804f93cc4f094cf4f77d3f3263575316b
WIP: implement data streams