[Feature] Skin engine Themes grab text from a file %ft(file, line) WIP

allow the skin engine to read text files and return a particular line

you then can use ss on that string to allow display of strings from the file
(Playername comes to mind)

able to be used as conditional
%?ft(filename)<Found|Not Found>

if (selected) line of file is empty the tag is treated as #COMMENT

scroll timeouts now persist thru trackchange

bugfix:
%t(n)%?x<text|text>
would ignore the specified timeout defaulting to 2 seconds

playername.txt generated at boot if it doesn't exist contents: 'RockBox!'

Change-Id: I961910e01be052ef902f77e6d92fc3e367ffe9d0

wps/cabbiev2.220x176x16.wps

@@ -62,7 +62,7 @@
 %s%al%?it<%it|%fn>
 %s%al%?ia<%ia|%?iA<%iA|%?d(2)<%d(2)|%(root%)>>>
 
-%s%al%Sx(Next Track:)
+%s%t(300)%al%Sx(Next Track:);%s%al%t(1)%ft(.rockbox/playername.txt)
 %s%al%?It<%It|%Fn>
 #
 # Track Info - No Album Art
@@ -71,5 +71,5 @@
 %s%ac%?it<%it|%fn>
 %s%ac%?ia<%ia|%?iA<%iA|%?d(2)<%d(2)|%(root%)>>>
 
-%ac%Sx(Next Track:)
+%ac%t(300)%Sx(Next Track:);%ac%t(1)%ft(.rockbox/playername.txt)
 %s%ac%?It<%It|%Fn>