A minor release to improve parsing, construction, and modification.

• Greatly improved doc comments
• New Parse() and TryParse() overloads taking SemVersionStyles
  • SemVersionStyles provide greater flexibility in what formats to accept (feature #38)
  • Improved performance and more detailed exception messages (feature #62)
  • New methods enforce rule about leading zeros in prerelease identifiers (bug #16)
  • Old Parse() and TryParse() overloads marked obsolete
• New With(), WithParsedFrom(), WithX(), WithoutX() methods to replace Change() method (feature #65)
  • New methods fully validate parameters to prevent invalid versions
  • New method names clearly indicate that the method does not mutate the existing SemVersion
  • Old Change() method marked obsolete
• Added PrereleaseIdentifiers property providing access to individual identifiers (feature #37)
• Added MetadataIdentifiers property providing access to individual identifiers (feature #37)
• New Metadata property for consistent terminology use matching the semver spec
  • Marked Build property obsolete
• Added IsPrerelease and IsRelease properties (feature #44)
• New constructor overloads and SemVersion.ParsedFrom() method (bugs #40, #41)
  • New overloads accept prerelease portion and metadata as individual identifiers
  • New overloads validate all parameters to prevent invalid semantic versions
  • Marked old constructor overload obsolete
• SemVersion now implements IEquatable<SemVersion> (feature #34)
• New SemVersion.FromVersion() and ToVersion() methods for conversion from and to System.Version (bug #32)
  • Corrects the mapping between version parts
  • Marked old constructor obsolete
• Added .NET Standard 2.0 assembly version to avoid warnings about .NET Standard 1.0 (feature #30)
• Assembly version fixed at 2.1.0.0 until v3.0 (bug #61)
• Marked implicit conversion from string obsolete (feature #46)
• Improved hash code calculation