Shorten 'from' in adjustOHLC and getDividends

Setting from="1900-01-01" resulted in a bad request. Pre-1950 should be
adequate for the majority of companies.

See #157.

R/adjustOHLC.R

@@ -12,8 +12,8 @@ function(x,
       ratio <- Ad(x)/Cl(x)
     } else {
       # use actual split and/or dividend data
-      div <- getDividends(symbol.name, from="1900-01-01")
-      splits <- getSplits(symbol.name, from="1900-01-01")
+      div <- getDividends(symbol.name, from="1949-01-01")
+      splits <- getSplits(symbol.name, from="1949-01-01")
       # un-adjust dividends for splits (Yahoo already adjusts div for splits)
       # do not use split.adjust=FALSE in getDividends call, which would
       # download the split data twice.

R/getDividends.R

@@ -33,7 +33,7 @@ function(Symbol,from='1970-01-01',to=Sys.Date(),env=parent.frame(),src='yahoo',
 
   # dividends from Yahoo are split-adjusted; need to un-adjust
   if(src[1] == "yahoo" && !split.adjust) {
-    splits <- getSplits(Symbol.name, from="1900-01-01")
+    splits <- getSplits(Symbol.name, from="1949-01-01")
     if(is.xts(splits) && is.xts(fr) && nrow(splits) > 0 && nrow(fr) > 0) {
       fr <- fr / adjRatios(splits=merge(splits, index(fr)))[,1]
     }