Change hint on bed format to indicate correct bed4.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "vplot"
-version = "0.3.421"
+version = "0.3.422"
 authors = ["Spencer Nystrom <nystromdev@gmail.com>"]
 edition = "2018"
 

README.md

@@ -74,6 +74,7 @@ Like examples? Here you go:
 ``` sh
 
 # regions must be equal width
+# and must be in bed4 format
 $ cat regions.bed
 chr2L   100 200 .
 chr3R   5000 5100 .
@@ -198,7 +199,7 @@ ARGS:
             Path to an indexed bam file
 
     <regions>    
-            Path to a bed file (must be in bed4 format: chr, start, end, strand) Of a region (or regions) in which to
+            Path to a bed file (must be in bed4 format: chr, start, end, name) Of a region (or regions) in which to
             generate the vplot. If using multiple regions, all entries must be the same width. If setting multiple
             regions, reads will be aggregated into a single matrix unless `--multi` is set
 ```

src/main.rs

@@ -14,7 +14,7 @@ struct Cli {
     /// Path to an indexed bam file
     #[structopt(parse(from_os_str))]
     bam: std::path::PathBuf,
-    /// Path to a bed file (must be in bed4 format: chr, start, end, strand) Of
+    /// Path to a bed file (must be in bed4 format: chr, start, end, name) Of
     /// a region (or regions) in which to generate the vplot. If using multiple
     /// regions, all entries must be the same width. If setting multiple
     /// regions, reads will be aggregated into a single matrix unless `--multi`