update usage in readme

Readme.md

@@ -9,6 +9,7 @@ git clone https://muhq.space/software/allocbench.git
 ## Usage
 
 	usage: bench.py [-h] [-s] [-l] [-r RUNS] [-v] [-b BENCHMARKS [BENCHMARKS ...]]
+	                [-ns] [-sd SUMMARYDIR] [-a]
 
 	benchmark memory allocators
 
@@ -19,4 +20,8 @@ git clone https://muhq.space/software/allocbench.git
 	  -r RUNS, --runs RUNS  how often the benchmarks run
 	  -v, --verbose         more output
 	  -b BENCHMARKS [BENCHMARKS ...], --benchmarks BENCHMARKS [BENCHMARKS ...]
-	                        benchmarks to run
+	  benchmarks to run
+	  -ns, --nosum          don't produce plots
+	  -sd SUMMARYDIR, --summarydir SUMMARYDIR
+	  directory where all plots and the summary go
+	  -a, --analyse         collect allocation sizes