update pshell explorer and data import, misc. improvements

FEATURES

- pshell: convert scienta data to true counts
- pre-process: add gauss2_reduction data reduction function
- anglescan: add set_contrast and normalize_strip_phi functions
- explorer: show info about multi-region scans
- documentation: add detailed instructions for angle-scan processing

BUGFIXES

- explorer: fix attributes notebook
- pshell: fix progress bar
- elog: increase the number of accepted attachments

pearl/preferences/pearl_explorer/attr_filter_pearl.itx

@@ -0,0 +1,32 @@
+IGOR
+WAVES/T	attr_filter_summary
+BEGIN
+	"MonoEnergy"
+	"MonoGrating"
+	"FrontendHSize"
+	"FrontendVSize"
+	"ExitSlit"
+	"ManipulatorTheta"
+	"CenterEnergy"
+	"ManipulatorTilt"
+	"ManipulatorPhi"
+	"AcquisitionMode"
+	"ChannelBegin"
+	"ChannelEnd"
+	"CenterEnergy"
+	"PassEnergy"
+	"NumChannels"
+	"NumFrames"
+	"NumIterations"
+	"StepSize"
+	"NumIterations"
+	"AnalyserSlit"
+	"SampleCurrent"
+	"LensMode"
+END
+X SetScale/P x 0,1,"", attr_filter_summary; SetScale y 0,0,"", attr_filter_summary
+
+WAVES/T	attr_filter
+BEGIN
+END
+X SetScale d 0,0,"", attr_filter