Increase minimal required Rust version (due to dependencies)

.travis.yml

@@ -1,21 +1,12 @@
 language: rust
 rust:
-  - 1.24.0
+  - 1.32.0
-  - 1.25.0
-  - 1.26.0
-  - 1.27.0
-  - 1.28.0
-  - 1.29.0
-  - 1.30.0
-#  - stable
-#  - beta
-#  - nightly
 
 env:
   - ARCH=x86_64 FEATURES=''
-#  - ARCH=i686 FEATURES=''
+  - ARCH=i686 FEATURES=''
-#  - ARCH=x86_64 FEATURES='serde1'
+  - ARCH=x86_64 FEATURES='serde1'
-#  - ARCH=i686 FEATURES='serde1'
+  - ARCH=i686 FEATURES='serde1'
 
 addons:
   apt:

README.md

@@ -37,7 +37,7 @@ The following optional feature is available:
 
 ## Rust version requirements
 
-Rustc version 1.24 or greater is supported.
+Rustc version 1.32 or greater is supported.
 
 
 ## Related Projects