Merge branch 'master' into rocket-0.4

# Conflicts:
#	Cargo.lock
#	Cargo.toml
#	src/api/core/mod.rs

Cargo.toml

@@ -9,7 +9,7 @@ rocket = { version = "0.4.0-rc.1", features = ["tls"] }
 rocket_contrib = "0.4.0-rc.1"
 
 # HTTP client
-reqwest = "0.9.4"
+reqwest = "0.9.5"
 
 # multipart/form-data support
 multipart = "0.15.3"
@@ -26,7 +26,7 @@ chashmap = "2.2.0"
 # A generic serialization/deserialization framework
 serde = "1.0.80"
 serde_derive = "1.0.80"
-serde_json = "1.0.32"
+serde_json = "1.0.33"
 
 # A safe, extensible ORM and Query builder
 diesel = { version = "1.3.3", features = ["sqlite", "chrono", "r2d2"] }
@@ -36,7 +36,7 @@ diesel_migrations = { version = "1.3.0", features = ["sqlite"] }
 libsqlite3-sys = { version = "0.9.3", features = ["bundled"] }
 
 # Crypto library
-ring = { version = "0.13.2", features = ["rsa_signing"] }
+ring = { version = "0.13.5", features = ["rsa_signing"] }
 
 # UUID generation
 uuid = { version = "0.7.1", features = ["v4"] }
@@ -56,11 +56,14 @@ jsonwebtoken = "5.0.1"
 # U2F library
 u2f = "0.1.2"
 
+# Yubico Library
+yubico= { version = "=0.4.0", default-features = false }
+
 # A `dotenv` implementation for Rust
 dotenv = { version = "0.13.0", default-features = false }
 
 # Lazy static macro
-lazy_static = "1.1.0"
+lazy_static = "1.2.0"
 
 # Numerical libraries
 num-traits = "0.2.6"
@@ -84,3 +87,6 @@ lettre_email = { git = 'https://github.com/lettre/lettre', rev = 'c988b1760ad81'
 
 # Version 0.1.2 from crates.io lacks a commit that fixes a certificate error
 u2f = { git = 'https://github.com/wisespace-io/u2f-rs', rev = '75b9fa5afb4c5' }
+
+# Allows optional libusb support
+yubico = { git = 'https://github.com/dani-garcia/yubico-rs' }