Add some methods from PositionableStream used by Tonel (ref #208)

(cherry-picked from commit 5cbf1d51680dbd029b87f476ab18b50d4159b343)

Author: j4yk

src/FS-AnsiStreams.package/TPositionableStream.trait/instance/match..st

@@ -0,0 +1,16 @@
+positioning
+match: subCollection
+	"Set the access position of the receiver to be past the next occurrence of the subCollection. Answer whether subCollection is found.  No wildcards, and case does matter."
+
+	| pattern startMatch |
+	pattern := ReadStream on: subCollection.
+	startMatch := nil.
+	[pattern atEnd] whileFalse: 
+		[self atEnd ifTrue: [^ false].
+		(self next) = (pattern next) 
+			ifTrue: [pattern position = 1 ifTrue: [startMatch := self position]]
+			ifFalse: [pattern position: 0.
+					startMatch ifNotNil: [
+						self position: startMatch.
+						startMatch := nil]]].
+	^ true

src/FS-AnsiStreams.package/TPositionableStream.trait/instance/upToAll..st

@@ -0,0 +1,14 @@
+accessing
+upToAll: aCollection
+	"Answer a subcollection from the current access position to the occurrence (if any, but not inclusive) of aCollection. If aCollection is not in the stream, answer the entire rest of the stream."
+
+	| startPos endMatch result |
+	startPos := self position.
+	(self match: aCollection) 
+		ifTrue: [endMatch := self position.
+			self position: startPos.
+			result := self upToPosition: endMatch - aCollection size.
+			self position: endMatch.
+			^ result]
+		ifFalse: [self position: startPos.
+			^ self upToEnd]

src/FS-AnsiStreams.package/TPositionableStream.trait/instance/upToPosition..st

@@ -0,0 +1,4 @@
+accessing
+upToPosition: anInteger
+	"Answer a subcollection containing items starting from the current position and ending including the given position. Usefully different to #next: in that in the case of MultiByteFileStream, and perhaps others, positions measure in terms of encoded items, while #next: convention is to name a number of items, independent of their encoding in the underlying buffer."
+	^ self next: anInteger - self position

src/FS-AnsiStreams.package/TPositionableStream.trait/methodProperties.json

@@ -4,4 +4,7 @@
 	"instance" : {
 		"back" : "jr 3/7/2017 17:08",
 		"errorCantGoBack" : "jr 3/7/2017 17:03",
-		"reset" : "jr 6/7/2017 13:03" } }
+		"match:" : "jr 12/9/2018 19:43",
+		"reset" : "jr 6/7/2017 13:03",
+		"upToAll:" : "jr 12/9/2018 19:43",
+		"upToPosition:" : "jr 12/9/2018 19:43" } }