fix improper use of whitespace in README.md files

The use of the markdown trailing whitespace to indicate
line break should NOT be done when the following line is empty.

This removes such improper use of whitespace in README.md files.

2013/dlowe/README.md

@@ -24,7 +24,7 @@ make
 ./dlowe 16 32 64 128
 ./dlowe 16 32 64 128 256
 ./dlowe 16 32 64 128 256 512
-./dlowe 0 
+./dlowe 0
 
 echo "sparkline of file sizes: $(wc -c * | awk '{print $1}' | xargs ./dlowe)" # or ./sflen.sh
 ```
@@ -68,7 +68,7 @@ something funny (or will it ? :-) ) and when will it do nothing?
 
 ## Judges' remarks:
 
-We liked how this entry used Unicode, specifically UTF-8, in a somewhat obfuscated way. 
+We liked how this entry used Unicode, specifically UTF-8, in a somewhat obfuscated way.
 
 Also, why doesn't it crash but instead produces a correct output when called
 with one argument or when all arguments are equal?
@@ -82,10 +82,10 @@ int main() {
 }
 ```
 
-with gcc and clang. 
+with gcc and clang.
 
 
-With GCC (4.7.2), we get 
+With GCC (4.7.2), we get
 
 ```
 -2147483648 -2147483648 -2147483648